1. Field of the Invention
The present invention relates to an operating lamp, and more specifically, to an operating lamp with adjustable light sources capable of generating a light field of a Gaussian distribution.
2. Description of the Prior Art
In modern society, illumination devices have become indispensable in our daily life. In a dark environment, an illumination device is usually required for people to engage in certain activities, such as a surgical operation. Therefore, many auxiliary devices for providing light are manufactured accordingly. An optical system for surgical operation application is a representative example.
In general, a surgical operation requires optical systems having specific light-technological properties (for example, shadowless, luminescent, etc.). Thus, a prior art optical system comprises a plurality of light sources for fulfilling the requirements. Please refer to FIG. 1. FIG. 1 is a perspective view of an optical system 1 according to the prior art. The optical system 1 comprises a plurality of light sources 2, 3 (only three are shown in FIG. 1). As shown in FIG. 1, the light sources 3 are disposed around the light source 2 symmetrically, and each light source 3 is pivotally connected to the light source 2 so that the tilted angle of each light source 3 with respect to the light source 2 can be adjustable. Each of the light sources 2, 3 comprises an LED 4 and a condensing lens 5. A position of each LED 4 relative to the corresponding condensing lens 5 is fixed, and an optical axis of each LED 4 is aligned with an optical axis of the corresponding condensing lens 5 for providing a light field with a light intensity of a substantial Gaussian distribution in a target area.
During a surgical operation, a doctor usually needs to expand the light field to get a better vision of the target area. At this time, the doctor can adjust the tilted angle of the light sources 3 with respect to the light source 2 via rotating the light sources 3 relative to the light source 2 so as to change the light field diameter.
However, that will cause the light intensity distribution of the light field varying from the substantial Gaussian distribution to a non-Gaussian distribution in the target area due to the angle variation between the light source 2 and the light sources 3. Thus, although the light field can be expanded to a desirable size via adjusting the tilted angle of the light sources 3 with respect to the light source 2, the center light intensity of the light field is greatly reduced accordingly because the distribution of the light field is no longer substantially Gaussian.